The polymerization of olefinic monomers can be carried out using Ziegler-Natta catalyst systems. They can also be prepared using metallocene type catalyst compositions. Conventionally, such polymers are compounded with additives by dry blending the polymeric material in the form of pellets or powder with the additives and then melt blending them to form a well dispersed compounded olefin polymer.
Colorants that add aesthetic appeal to polymeric material, are also compounded first by dry blending and then by melt blending with the polyolefinic material. Another method to color olefin polymers is to melt blend them with colored master batches. Some polymers such as UHMWPE are difficult to melt blend and hence they have a limitation in adding colorants in their matrix. Also, the conventional method of coloring may result in non-uniform dispersion of the colorant.
Several entities, today, have their trademarks displayed on their advertisement billboards and product packaging. By rule, the color used in trademarks must not deviate. If the plastics used to prepare the packaging material exhibit even a slightly different color, the batch will be rejected. The conventional methods for coloring plastics do not always result in the same color and hence, cause a lot of wastage.
Hence, there is a felt need to provide for a method for coloring of olefin polymers that will result in homogeneous dispersion of the colorant in the polymer, at the same time, the plastics retain their properties in their colored form. The method of coloring should not cause any adverse effects on the polymers and should exhibit substantially the same color shade batch after batch.